Distributed Caching in LTE RAN for Backhaul Strain Reduction
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Solution Overview
Problem
The existing method of content delivery in LTE RANs faces challenges with high latency and network congestion due to the strain on carrier's CN and RAN backhaul, as RAN caches have limited capacity and often result in cache misses, leading to increased traffic through the CN and Internet CDNs.
Innovation Solution
A method where content data is divided into segments and distributed across multiple eNBs in the RAN, allowing for acquisition from neighboring nodes to improve cache hit ratio and reduce the load on the RAN-CN link, with optional retrieval from the CN or CDN if segments are not available locally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If content data is fetched from Internet CDNs through CN and RAN backhaul, then cache hit ratio is improved at RAN nodes, but network congestion and delay increase due to strain on carrier's CN and RAN backhaul
Solution Approach 1:
The patent divides content data into multiple segments and distributes them across different RAN nodes. When a cache miss occurs at one RAN node, the needed segments can be retrieved from neighboring RAN nodes rather than fetching complete content through the CN backhaul, thereby reducing latency while maintaining cache hit ratio.
Solution Approach 2:
The patent introduces an intermediary mechanism where RAN nodes directly exchange data segments with neighboring nodes through lateral communication. This bypasses the CN backhaul for segment retrieval, reducing network congestion and delay while still achieving content delivery through distributed caching.
2Quantity of substance
If RAN caches store only thousands of videos with smaller size, then caching capacity at RAN edge is achieved, but cache hit ratio decreases compared to large-sized caches in Internet CDNs
Solution Approach 1:
By segmenting content data and distributing segments across multiple RAN nodes, the system effectively increases the total caching capacity available to any given node. A node can retrieve segments from neighboring nodes, making the distributed cache system function as a larger unified cache, thereby improving cache hit ratio without requiring each individual RAN node to have large storage capacity.
Solution Approach 2:
The patent merges the caching capabilities of multiple RAN nodes into a distributed cache system. When one node experiences a cache miss, it can retrieve segments from other nodes' caches, effectively combining their storage resources. This collective caching approach improves the overall cache hit ratio while maintaining the constraint of limited individual node capacity.
3Reliability
If data is retrieved from CN or Internet CDNs when RAN cache miss happens, then complete content delivery is ensured, but significant strain is placed on carrier's CN and RAN backhaul
Solution Approach 1:
The system segments content data and distributes it across multiple RAN nodes. When a cache miss occurs, only the specific missing segments need to be retrieved from neighboring nodes rather than fetching complete content through the CN backhaul. This reduces the strain on network infrastructure while ensuring complete content delivery can still be achieved.
Solution Approach 2:
The patent implements preliminary distribution of content segments across multiple RAN nodes before requests arrive. This proactive segmentation and distribution ensures that when requests come in, the data is already positioned at the edge, reducing the need for backhaul traffic and minimizing strain on the CN and RAN backhaul during peak concurrent request periods.
Data Source
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AI summary
The embodiments of the present invention provide a method of content delivery in LTE RAN, an eNB and communication system. The method includes: receiving, by an eNB from an UE, a client request for requesting content data; checking a segment map according to the client request; acquiring the plurality of segments from one or more eNBs of the RAN according to the index information in the segment map; generating the content data by using the plurality of segments; sending the content data to the UE. In this invention, a content data is divided into a plurality of segments and the segments are distributed in a RAN. Furthermore, the content data is acquired from neighboring nodes of RAN as much as possible, such that cache hit ratio is improved and the link between RAN and CN is saved.